It is understood his body had been in the apartment for several days before being discovered.

In 1987 Ferguson was jailed for 14 years after he and male lover Alexandria George Brookes abducted three children from NSW, taking them to an Ascot motel in inner Brisbane where the children were raped and subjected to vile and indecent acts.

Ferguson claimed he was innocent, accusing one of the boys he molested of committing the crimes but a jury found him guilty of all counts of abduction and assault of the three children. He was sentenced to 14 years' imprisonment by a judge who noted there was no chance he would be rehabilitated.

He was released in 2004, but authorities were forced to move him several times from towns including Ipswich and Toowoomba due to public anger at his presence.

He was eventually relocated to NSW.

In November 2005, Ferguson was charged with sexually assaulting a five-year-old girl at her home in the Queensland town of Dalby. In a rare legal move, the judge granted Ferguson a trial without a jury, as he considered Ferguson would not receive a fair trial by jury.

Ferguson was released when the judge found that while the girl had been molested while Ferguson and fellow convicted child sexual abuser Allan Guy had been at her house, it could not be proved beyond reasonable doubt that Ferguson had been responsible.

Convicted paedophile Dennis FergusonSource:The Daily Telegraph

In 2009, there was outrage when Ferguson's presence was revealed to neighbours in the Sydney suburb of Ryde, prompting a public outcry that forced the NSW government to change laws in order to relocate him.Ferguson said at the time he posed no threat to children in the general community, but would consider chemical castration if it was deemed safe and effective.

He also said people who were sexually attracted to children, over time, lost interest in them.

Ferguson last made headlines in July 2012, when he was spotted at Circular Quay selling biscuits to raise money for the RSPCA.